Rotating Control Device Cooling Mandrel for Bearing Temperature Reduction
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Solution Overview
Problem
Modern rotating control devices (RCDs) face challenges in operating effectively at high pressures and rotational speeds due to elevated bearing temperatures, which shorten bearing life, especially in land applications where heat removal is limited to radiation and convection, and require complex external oil circulation and cooling systems.
Innovation Solution
A removable cooling mandrel assembly that allows the circulation of water or clean drilling fluid past the bearings, supplied by a simple low-pressure pump from the drilling rig system, to enhance heat removal and extend bearing life without the need for external pressure support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RCDs operate at higher pressures and higher rotational speeds, then productivity and sealing effectiveness are improved, but bearing operating temperature increases significantly, shortening bearing life
Solution Approach 1:
The cooling system is segmented into multiple cooling channels formed by the cooling mandrel and housing, allowing cooling fluid to flow through distinct paths that efficiently remove heat from bearing surfaces and sealed components without interfering with the high-speed rotation function
Solution Approach 2:
A cooling mandrel is introduced as an intermediary component between the bearing assembly and the external cooling fluid supply. The mandrel directs cooling fluid to critical heat-generating areas, acting as a mediator that transfers thermal energy away from the bearings while allowing the bearings to continue their high-speed rotation function
2Temperature
If external oil circulation and cooling systems are added to remove heat, then bearing temperature is reduced, but device complexity increases significantly
Solution Approach 1:
The cooling function is merged with the existing RCD structure by integrating cooling channels into the housing and using the cooling mandrel as part of the bearing assembly. This combines the cooling function with the existing mechanical structure, eliminating the need for separate external cooling systems
Solution Approach 2:
The cooling mandrel serves multiple functions: it acts as a structural support for the bearing assembly, a conduit for cooling fluid distribution, and a heat sink itself. This multi-functionality reduces the need for additional dedicated cooling components, simplifying the overall system
3Loss of energy
If cooling fluid circulation is implemented through the mandrel, then heat removal efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The cooling system uses hydraulic principles by circulating cooling fluid through channels in the cooling mandrel and housing. The fluid flow paths are designed to maximize heat removal efficiency through proper channel sizing and placement, while the channels are manufactured using standard hydraulic machining techniques
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The cooling mandrel effectively reduces bearing operating temperatures, improving sealing performance and extending the life of RCDs in high-pressure and high-RPM applications, while simplifying the system by eliminating the need for external oil circulation and pressure support.
Implementation Method 1
The cooling mandrel allows circulation of water or clean drilling fluid past the bearing contact surfaces and seal contact surfaces to ensure efficient heat removal.
Implementation Method 2
The cooling mandrel effectively reduces bearing operating temperatures, improving sealing performance and extending the life of RCDs
Data Source
AI summary
A removable cooling mandrel assembly for a rotating control device for use in a drilling system. The present disclosure provides an outer swivel housing enclosing an elongate passage and connected to the uppermost end of an upper housing of the rotating control device. An inner swivel mandrel is mounted in the elongate passage of the outer swivel housing for rotation relative to the outer swivel housing and may be connected to an RCD mandrel of the rotating control device to which the outer swivel housing is connected. A tubular cooling mandrel extends from the inner swivel mandrel out of the outer swivel housing to reduce operating temperatures thereby increasing bearing performance and life and seal life.